Telephone-exchange system.



F. W. DUNBAR. TELEPHONE EXCHANGE SYSTEM. APPLIOATION FILED JAN.13, 1905.

Patented Mar. 23, 1915.

inventor: f 'rancz's (Dunbar Wtnesses:

F. W. DUNBAR. TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED JAN.13,1905' 1,1 33,1 1 1 Patented Mar.23, 1915.

Inventor. Ex Francis Dun/1a r Wly.

Witnesses m-k mamdm/ @JM P. W. DUNBAR. TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED JAN.13, 1905. 1 1 33 1 1 1 Patented Mar. 23, 1915. a SHEETS-8HEE'I a.

e witnessed jest is accomplished by ha ring the selecting mechanism assi'iciated with the lines select the jacks in their ord r, -;ay from right to left rather than proinisciiously, so that the answering-ends of the co 'ds will lead to the answering iacks in an orderly fashion one after the other, in aid l' eing indiscrimi nately distributed into association with the answering-jacks of the switch-hoards, according to present practice, for with mult ple svvitclrlioaids now ii use the indis rimina distribution of the answering-ends of the cords is accompi'inied by an inter-weaving of these cord ends, so that it is dillicult in ellecting disconnecting to picli' out the ('fOnllUPlllEg tftidS that ma ice with the answering ends, which confusion is greatly lessened, if not altogether dispensed with, by means of my invention.

The present invention (which I shall describe in ciainection with metallic telephone lines, the application of the invention to grounded lines being well understood by those skilled in the. art, finds its einbodr merit in a pair of moving line terminals for each telephone line and motormechanism jointly controlled by answeringjack circuit apparatus and :1 su scribers apparatus for cilecting engagement betivcen these terminals and the answeringterminals of an idle answering-jack circuit, that may be brought into engagement with the said line-termin ls by the movement of the latter. This m tor mechanism desirably not constantly operated, but is preferably only operated on the initiation of a call, to which end I associate the operating winding of each mecl'ianism with the line in such a way that when the line circuit is operatively metallically closed at a suhscribeus station, the circuit through the said winding will be complete and the motor mechai'iisin set into operation. The continuity of this circuit, including the winding, not only dcpends upon the suhscribens switch-hook. but lso upon circuit connections at the exchange controlled by the answeringjack circuits. The presence of some one ol these circilit-connections is necessary to the coin pletion of the circuit through the winding, and such circuit connections are always placed in position to be included in circuit the winding by the apg'iaratus of the anva'ering-iaclt Ull'(flll1h when the said anmvering iaiili circuits are busy. This a pparatus, when their associate answering jack cirruits are idle, serves to elicit removal of these latter circuit connections, which circuit connections are preferably located altogether at the oliice. l lach switching device operated by this motor winding is provided not only with the line-terminal, but also has a terminal of a circuit controlling the winding. which rides over tern'iinals of the ofllce connections spoken of. whereby circuit is maintained through the winding as long as the said otlice connections are maintained complete by the apparatus associated with busy answering-jack circuits, whereby the line-terminals are caused to pass over the terminals of the answering ends of the busy answering-jack circuits. \Vhen the said terminal of the controlling circuit comes into contact with a terminal of an officeconnection that is rendered incomplete by the apparatusof an idle answering-jack, obviously, the circuit that controls the Winding is then open and the movement of the traveling switching mechanism ceases, such cessation occurring with the linc-terminals of the calling line in contact with the terminals of the answering end of the idle answering-jack circuit.

I preferably employ line-relay mechanism for the control of the motor winding provided for each line and the circuit that controls said motor winding is, therefore, preferably a local circuit, the winding displacing the line signal, as by means of my invention the only calling signals that need be provided may be associated with the answering-jack circuits, though I do not Wish to be limited to this embodiment of the invcntion. The said line-relay mechanism governs switching mechanism that governs the continuity of said controlling local circuit at one point, the balance of the control being obtained by the traveling terminal of the winding and the oflice connections, whose operative condition is determined by the answering-jack circuits, all as hitherto set forth. In order that special signaling lamps may not be required, the traveling switch contacts that have been described are also accompanied by another moving switch contact under the control of the motor winding, which latter contact cooperates with terminals of signaling circuits associated with the answering-jack circuits, so that, when the movement of the traveling switching mechanism is arrested, the circuit through the calling signal will be completed to notify the operator of a new call. A line-jack is permanently associated with each line in addition to the traveling terminals of each line, this being an important feature of my invention.

While my invention has found particular utility in connection with and is well adapted for a 'iplication to multiple switch-- hoard systems, it has other applications which will he readilv understood to those skilled in the art. Where the invention is employed in connection with multiple switch-board systems the tele 'ihone lines may be connected with the dill erent sections of the switch-board in accordance with any suitable practice, as the apparatus of my irivention does not interfere i any way with the usual operation and arrangement ot'the ans atmn 10 the may i 1 UHEYHQ ntmndcd to by nav have I is in 01x21 1y :11 num er ni' 1 opemt m muzuw and mporl SW 43 1' m I l MC law inch 511+:

I I- h aim t relation with respect to the lines, vnereby the ?1 H1 5.? hut tion of Um Inward :u'u tin BCUUHH m'u the tcs e l, 4 Min mph);

."Jin gin per vision i i nveutimx.

humus.

(V a k, I) L1 Ned Subscriber gh I heat We 01 11W impel an ha 111 supplied 43PM! mu vision 01' emplu 30 very do any.

OPP}

w hum" Hus U! QIVOUUS- Ark 0 1i. 1

wv min :1 1 a as 111)- power-t; in 1121 0 u? amount of rmz ncss 105 From 2,1 wu'i min maxi

may

21w mm;-

giwxuyng upon a fit) change--can handle the entire number of calls by Walking from section to section and picking up the various calls as they may come in. At all such times the elliciency of the operators-reckoned on a basis of number of calls answered per hour---is very low, the result being that the aieiage number of calls handled per operator per hour througl'iout, the twenty-four is less than half the number which the average opcratl'ir able to handle ellicientl were she kept uni formly bu y.

By means of my inv ntion i am enabled to distribute the allso that during the night hours all the callsv will appear at the tirst section of the sn'itclrboard or at the first tvvo or three alcpending upon the size of the exchange and the volume ol' night business, so that. as the busincss increases, operator alter operator may he added as reuuirett--the first. or lower numbered sec tions being aluavw: llfl lv' and the higher nl'mber sectuiim: l hung gradually into cperz ti n as the busy hours approach. I ZUl'l thus enabled to secure the same average number 0t calls answered per o 'ierator per hour throughout the twenty-tour as is socured during the hi "cst hour f the dayresulting in a dccrec; in cperatinn expense of 50% or more. 1 do not contemplate, however, in large excl-liners providing the necessary switching facilities. so that each line may be connccterl with any one oi" all the answering iacl;s. although in sniallcr switch-boards i would he prcl'crahlc to do so. In large exchanges I prefer to divide the lines into groups of several hundred each and divide the amc ingjachs into a corresponding Illllll /ti" of groups so that any line in a ccrtain group may la: connected with any ansvvering jacl; ass iuul to that group, it the lower numbered arise-cringiaclcs of that group already be busy. ll that particular onc be not bury. the first idle ansucriirf -act: thus select d. will automatically nial c-nnncction with a calling subscriber. For cvaniplc- I will assurnc an exchanu' o tour thousand live hundred lines and I l' Yl Klt .1. gro p oi thirty ausvveringjaclis tor chi-h hundred lin sclcoty ans c making two huialrm cqually betwccn nine jacks in all. lihulc-l or thirty 2Illf$"( swticn (instcaz'l ol' thrcc a vi iltlllu. lug-jacks to i iuiulrcd to liw hunm'cil as hithcrtol and ten t the opcrator, During thc llltj'lll lit'iurs.v therefore. all e la \vill app a: at th b a l'tl, unh s in first section ol' lhc some particular group el' til-olllllifl lt'll lin s there Were more than threc calling lines nuiltaneously conncctcil in conversa4icn-in which case the fourth line of that group making a call while calling 7 the other three parties of the some group were still connectack circuits oi. one til'th ed, would indicate at the first position of the second section. A fifth call from the same group ecurring While the other four were still conversing, would appear at the second position of the second section and would necessitate the operator leaving her positi n at the first section to attend to it. buch a corulition would not be apt, however, to arise, as it would require (assuming one operator only was needed for the business at this time) tlie-sixths of the total business which this single operator could etliciently handle, to origuiutc in a, group containing only cue-ninth oi" the total number of lines.

ln the example above hosen as an illustlntl iti l \vouhl cinplov selector switches, each comprising thirty tiOlIllL-S, that is, facilitl for onnecting thereto thirty answeringim l4 circuit '1 he first point of each so itch w uld he connected to the answeringia l; appearing at the fir t, opcrators position. he uzrl point bring connected with the anavlcrzng' jaclt a 'ipcaring at the second opt-muons position, em, tlielast three points of etch switch being divided between the twenty en operators positions at the dis cretion of the manager. Each section thus has three ansivcrin aclr circuits for each lines, it being apparinanager may so dixiliCtIitS at themto accomm0- ity of the 0ppr rvc a uniform numansuering-jack circuits for lines, or a number correctly proport i ncd to the business of each groupfor example, he may cut or render inoperatiw the lirst. second and third answeringoperator, the fourth, and sixth of a second operator, and the smentii, eighth and ninth ot a third operator. thus giving each of these three operators s cll'ccuvc or operative answeringjacl; c :ults and diminishing the number oi aiiw'cringjacits oi" each group of five l.-lltltl.t' l lines lvv one each It will be apparnt to those ski led in the crarors and still iwr of operative an; vul to meet hcr abilitics. Moreover, as

th iiv ansncriue h" circuits are provided for -h group oi live hundred hues, each,

it' itorhel to its m-ixunuin elliciene v, will be nimbl of hamluiux forty-five calls per hour, or a total of one thousand three hunllr ll lift calls during: the busy hour, repre wilting: an average of 7 calls per subscrihw during the lr'usy hour, or 21.0 per sulm-ribcv pcr (lay .Aniple margin is presout for a rut ction in the total number of 71IBV'UI RQJIUJlK circuits in service to an aver- .wgc ol seven or eight per operator and still furnish facilities for handling a greater ii an nor :1 grounded n (-aMHmE 3M0 116 1 tip cunt t dived not pymmim 11 contact button 14, the said element 13 having an elongated projection 15 for engaging the said contact 1 and any of the companion contact buttons 16 arranged in the same row, the number of contact buttons 16 equaling the number of tip contact buttons and equaling also the number of sleeve contact buttons, obviously. The projection 15 is so Wide that it makes connection ith one button in its path before leaving another The controlling circuit thus outlined is'nor mally open at the switch-arm 12. so that the controlling circuit is normally inell'ectire. \Vhen a subs iber initiates a call. the circuit is metallically closed at his station by the s\\itch-hook thereat. whereupon current finds path from the battery 11. through the winding of magnet or lined-clay 17. to the normal contact of the lower cuholl relay armature, o\ er the subscrilmr s line. to the normal contact ot the upper grounded armature 1 thence back to the ground at the battery 11, the relay 1? thereupon being energized to attract its armature mechani cally coupled with the switch-arm 12. there by closing the then only existing gap in the controlling circuit. As there is included the winding of relay 9 in this controlling circuit, the grounded contact of said relay is then engaged by its armature, whereby circuit is closed through the winding, 10. that may be traced from the said grounded con tact of the relay 9, to the front contact of the armature, constituting an armatureswitch, of relay 1?, to the bifurcated lazy arm 18, the contact for said arm with which said arm is normally held in engagement by the spring 19, the said winding 1 t the grounded battery 11. The armature of the winding 10 is thereupon attracted to move the contacts orterminals (i. 5 and 13, which are preferably arranged in straight line in a singie bar', nnchanicaly speaking, against, the force of an expansion spring 20, the said bar being notched at 21, so that e ch operation thereof bv the armature will etl'cct a movement of the contacts 5, 6 and 13 a distance equal to the distance between the centers of adjacent buttons 7, between the centers of adjacent buttons 8. and between the centers of adjacent buttons ll -lti. The detent 22 looks the bar in the position to which it has been advanced against the force of the spring-20. After each attraction.ot the armature of the relay. 10, the lazy arm 18 is moved away from its contact and stays away until the armature has been released, which operation is secured because the. free end of said lazy arm is bifurcated, an ere tension of said arnulturebeing interposed between the bifurcated members of the arm, it being the armature extension alone that has operating influence upon said arm. \Vhen the armature is released, it will again be attracted if the button 16 with which the extension 15 has now been placed in engagement happens to be grounded, it being grounded whenever the associate answeringjack circuit is busy.

In the illustration it is supposed that the first buttrn I) encountered by the element 11 is {ISSOt'ltltQtl with a busy answering-jack circuit and is. therefore. grounded, thereby t tttlr-l uing a n ther operation of the magnet 10 to bring said element 15 into contact with the next button 10. This button 16 happens to be associated with an idle answering-jack circuit or one that was idle prior to the inserti u of the answering plug 11' into a selected ,ia k. so that the c ntrolling circuit, of th windin I that included the high si -tame uia n t 9 tpened. the arn'iaturc ct said in IQ'llt't falling away from the Q'ltllltlltHl c nta t. thereby opening the circuit rn'itaiuiue' the winding I so that the aellcl'iir su it h is no longer t lre perated by the :uruature ot the nurlnet 10. whereby the liue-termiual- 3' are engaged with bulti us 8' T that are the terminals ol the idle answering jack circuit with whicu the buttin it; then in euuiujenient with the element or brush 1-- is assm'iated. When a alling line and its sele ting mechauisn' .iave st ught out an idle anscling-jack circuit. the brush 15 and th engaging" ecntact 16 et ect the calling: signal to the operate), as will we lu-reiualter set forth. l t under tccd that each row of buttons has associated therewith a motor 'operated switching device including eentacts 5, (i and 1 and that the ('utacts 1! that the brush 15 err gages are grounded when their answeringjack circuits are busy. The form of metor mechani m illustrated may he departed from and it is understcml that the means em ployed for securing an interruption of the motor windinc circuit. where th operation of the nlctor is thus controlled, may be departed fr m and equivalent apparatus well known to those skilled in the art employed. As hitherto stated. the first contact button 16 encountered by the brush 15 has been grounded because its auswering-jaek circuit is supposed to be busy. It will be seen that net only are the tip and sleexe contact but tons 7-8 of the various answering-jack cir ends of a group multipled together respectively, but that the associate buttons 16, equal in number to the said group of an s\\crin;Z-ja(:l( circuits. are also multipled, one multipled group btlonging to one answering-jack circuit, another nniltipled group belonging to anothe' answering-jack circuit. and so on, just as in the case of each group of multipled tip contact buttons and multipled sleeve contact buttons. so that any wiper 15 belonging to any motor IlItClIHHlSll'l, when encountering any contact button It; in its row that may be grounded, is caused by the mechanism to l'myvncl said contact. Apgjmratiiswha by a ground iilacmi upon a grmip ("I muitiplm'l (:ontavt', bui'tuns 1U limhaisxing am am busy ansa'mingflauk (fii'uuit is ilhiau'atei'l in detail, this group being the second group fHIIY] the right of t e llQK'hzHliHll shmwn at the lowvr lv'l lham (:01'1101' ui' Fig. l. Mr:- chanir'al zni'aiigQmi-nt anti rulativ (li ition of thov various groups; of (must ia'urns are unessmitial t0 the [Hflt'lIh'it 0i my i ma 'iiun so 1mg a mwtri al l'imviiwm Mn'iplished. Refining irmv m the phut-il Hnnociivns 42F ilif ,IIUHPS if l: 1? that are iml' aim; in tlm Fwm ml i-ir\\' wan flu: iighi in the h lt hand (mi-aw hf 2h fig NR2 ,iime is pr'm'irlwl ha HH'ii fil'iFWPlil'lfliai-h' (iiiiiit such :1 ('iIHiiHlii' a ihat im i (atoll at -25 that (hsii-ahl invhulez an armature 36. he said arrimtui'v's in anal mntzivfi. the alfcrnatv or front cniitavf l the iillilfl tum 7" whir-h minim-t mmwi'fml with ihc ill? spring (ii ("(Jliilfij 'l i Whii cuntaq-i liiittvns I"; in (llCU'ifTZll iiiKiLF-iilill fhvrmviih. so tlfl the wipm if) (if any which h1g5 movhani m making {whim-L with any (Tillmthm 16 ii: thP sn'mip (HHZW'iMl with the (OIl-l N'i l 23a Wiilhk mo ed ii an the human UL thus n; rail by mm of ihe inwlwi' l0 and the aw viatc mea-hanisn'i that has lie-3n spuviiiwl. When (h answering:- iawi; circuit has hem] svlevtwl. and thv :iit ufi relay hag tlilfllHUfl its ai'inritm'z. il'iiilij through ihv w n'liiig of magnet or relay 2.) awwviahwl 1th the armatui'h 537 is chwmh which viz-nit mai x10 travail from ihc grmnnh-d hattvrv' i1. (0 thv s'a'i l magnet win ling. tho ('IiHHOFll -H nl Q Iii Nilhliiil' with the slum lit'zlliil of tho am x'vzin 'avk. (la: gz'i'mm 0i hathns R. the wiper 5/ may IlW'lml with ma) ($12M huttwns. the terminal the armature to the grounded ii-r'minai ml the cuhnll' magnet 2, \vllti'illly the rainy i vnm'gixml.

uni, 0012mm; {Em Mm awi line :i and ihv :iz'izm answering-jack circuit and the terminals of a calling line may be connected automatically.

I have set forth in what manner and by what means a connection is put up between calling and called subscribers by the semiautomatic mechanism. I will now describe the preferred means by which the motor is again permitted to operate.

In the embodiment of the invention shown, the switching mechanism operated by the motor is a reciprocating mechanism, but I do not wish to be limited to such a mechanism, nor where the reciprocating mechanism is employed do I wish to be limited to the rectilineal motion thereof. Such mechanism being il nstratcd and preferably employed, I will de cribe not only the manner in which the. motor may be placed in condition to be operated, but also the mechanism by which the restoration of the reciprocating mechanism to initial position ma vcbe effected.

A releasing circuit is desirably employed which includes an electro-magnet 44 that controls the detent this mae'net (refer-- ring particularlv to the left oi Fig. l) con- 'trolling the said detent to cause the same to be Withdrawn from the tooth upon the bar section 21 with which it is enqaged to permit the coil-spring 30 to thrust the contacts 5, 6 and 13 to their initial positions.

W'hen the line-relav 17 has released the switch-arm 12 upon the sel ction of an answeringjack circuit by the line. the releasing circuit containing the magnet it partiallv closed. Vhen the connecting-plug ll has been withdrawn alter a conursation, subscriber A having restored his telephone receiver. the complete releasing magnet cir cuit is then established. which circuit may be traced from the grounded terminal of the winding of magnet ll, the switch-arm 12. the terminal 13, the buttons 16 in electrical connection therewith, 'the conductor tho armature Q6 and its normal or back contact, the contacts 28, the. armature L3? and its contact, to the grounded battery 11. The a rma ture of the magnet 44 is pivoted between its ends and is proiided with a spring catch or hook 45 that is adapted to ensaqe with the hook 46 upon the detent 22 which is pivoted between its ends. the said detent having a spring at one end to force the other end into engagement with a tooth upon the bar 21. The energization of the magnet 44 merely eflects connection between the hooks 4:5 and 46, whereby said detent. which is grounded, effects the completion of a. circuit which may be traced from the grounded detent to the hook 45, the relay 9, to the grounded battery 11, the said relay being thereby en ergized to move the switches 7 and J from their contacts and disconnect the answcrin jack circuit from the calling subscribers line, whereby the cut-oil relay 2 is denergized to restore its armature, and the relay 29 is included in open circuit to efl'ace the signal occasioned at the lamp The circuit including the releasing magnet 44 is broken when the magnet 2?) is included in open circuit, the opening in the circuit occurring at 27, whereby the relay 44 is deenergized, permitting the spring -17" to pull the detent out of engagement with the bar P section 2], so that the spring: 20 may restore the switching apparatus. the disengagement between the hooks iiiil? being occasioned by the projection 48 that engages the spring hook 4-5 when the restoration has been nearly completed, tlusreby restoring the selecting s\ .'itchin; mechanism to its initial idle condition. Thus it will be seen that by the removal of the armature 27 from its front contact. the ground is removed from the series of contacts ll; in el ctrical connection with the brush 13, so that any brush similar to 15 thereafter coming into contact with any of these Contact buttons, will not cause a continuation of the operation of the motor mechanism. but said motor n1echanism will thereupon be arrested as has been explained.

The enorgization of the releasing magnet cannot take place until after the calling subscriber has restored his telephone receiver. for the circuit of said magnet H depends upon the contact between the armature 26 and its normal or back contact, which cannot be had, in preferred practice, until the calling subscriber has restored his receiver, as heretofore specified, although the magnet l-l. while in readiness to be ell'cctive, is not ellertive until the operator has withdrawn the anrsxvering-plug. As soon, therefore, as the operator has inserted an airweringplug. the releasing magnet is beyond line control but is jointly controlled by one of the subscribers (in the embodiment of the ini entioo shown. the calling subscriber) and the apparatus ol. the operator. Prior to the insertion of the aii-iu'erinfrplu however, it is obi ions that the calling subscriber has .l'ull control over the releasini: magnet and may restore the switching mechanism associated therewith at any time before the ansurriugplug is inserted by restoring his telephone on its switch-hook.

The magnet 9 is desirably placed in series with the releasing magnet 44 associated with a busy answering iack circuit elsewhere in use. This circuit may be traced from grounded battery 11, through relay 9 of the calling line, alternate contact of 1?, switch member 13 with its brush 15. contact 16 enga 'ingz said brush to a similar contact 16 associated with said busy answering-jack, the switch members 12, and 15 of the line associated with said busy ansu'cringjaclt normal contact of 12, and relay 41 of said lattor-line, to grounci. Ths [magnet therefare, pz'efemb y woun to a low resists nos, while the magnet 9 is vYv'oin'ici Pompano tiveiy high resistance, whereby than: 44 is prevented-fromopara tion'v Ker.

in :series' with the magnet 9, but laitfi' magnet is permitted 12 opera-,2; when Jae magnet =4 is to operate, it encounters; lloiv resist-o ce path from the armature the battery, ti'zerma-gnet being giesuubij; of low resistance. If any perator should no provided with so-many "answerin -jaci; circuits as-to be beyond her capacity during the imsiest tin. I provide means whereby son-i2 of her-sinsweringjaci: circuits may ho out out of ice, so that selecting switches passing over a group-oi' co'zitacts will not select more than apredeterminednumber of idio answeringjack circuit& In this way work i:

operator has to do is accurately dju'sed to her maximixm capacity. Qhe means where- 'by the answering-jack circuits are made an responsive to a oaiiing iine resid gs 'mpos': ing upon each group of contacts'ifi associntec l with an ons\=-'ering-jack circuit to be eiide'd an artificial condi'ic'n whisk in the embodiment of the in' erz ion SilOW siiouizli be an artificial ground that may "cc thereupon by til-3, manually switches 47 that mo. of eleo'i'icaiconne ion with; groups of contact-s l6 acooi'npiish pose desireci. v In orcicrthat i-he'sw'tcii mumay noi throng somtion of i'he appm'atus. ing-jacks are busy, v 5 contacts without can 11;; answering-jack c not restored, I pro buttons 50' oonnec" Ml vii-,2 Wu}; of the. swifioi containing said SWl'iZx' opened by the armature of when attracted. sinoextx'a ronnectociwith the switch when said. 2191110211: has been fullest extenttiic motor .thmngh 27 opened calling 511' has T" 'ai'u-ra hook in tar-iii iearzi -Wiiy cured his oomiection, armatureswitch 12 is engaged 1: ac termimi of magnet H. This results in the closure of the circuit containing said 2 may be ii'aoedfrom but; r:- conductor- 52, con-wot brush element 13, armature-switch-3.2,,to a grounded The armature of magnet engages the parts m6. and

opens the switch 5-14 to de nergize sai mag net- 3 anti permit the spring ivto wnraw tiz ale-tent V with r'e-suli-s hitherto sp acifieci.

' jack stnmr .1. and cord strand a being om-' The apuarat-us illustrated upon the} is generally similai' to 'thogt" z 'The, buttons 14 the buttonsforming parts of thedeviosf v I 'iiowove i', siircctiy connected with thxm H through resistance 11 instad of 1 0513' grounded, The magnet 4 oing giiiectly grounded, 1s gioim' I rough the battery 11.- Theoontaot .=:ln. of: switch 51 is (ilrctly' groundod 7'6 (ibaing grounded thrqu'gh -t he'-' bat-' the cie-iersi 22 grounded throu h bother instead' 01' being directly grounded,- ar 1 Liza ground upon magneb 9 lihiI-El than by "way, of thobafliery; Theco docto (on the right) is rectiy insterrioi by way of theb'attery and' corresponding changes are madein the ch,

"nits 211d apparatus associated with tho sig-i '85" J what is Vk'no'wn as a; throo.

for use inmultiple switch- 4 a vv'iziohiineand cut-oif lays are em owed, the third answering-' I pio s d W1 ii third .coniactielement b (if and having separabio .oo'n'liec-' (conductor 0 normally in bl'i i1 t' moving member 0! oon- The switch 1 is a. trincluding the. Wind- 7 I 2'. Inasmuch as th' no oonciuctor a. are. addd f E- I, there is added memv'e 1-. 1 moving with the hermit 18.13;- z'uitipied rows ofcontaot' b'uttofifi which the temlina llfi is adaptd--' for ical connection... :ifiifijliinili buttons iimt belongs to an aim {:laceci in connection a. When the tlzivla-tne terminal 13' in, no of thesegroups of Con: HQ my). one z-e-iay E that corresponds in 9 of Fig. 1 isdenig'ized, '2', that corresponds in' "off relay Qof Fig? 1,--

eupon include 'irr-c'iif -=:oundeci bait'ery- 11, whereby; 1?", corresponding in fmfc e-resiay 1 2', is 'xolude'ri' fr'oink rine the. answering-iabkiP s of Fig. 1, parts similtiily d6? mgsimiiar functions;

:Ili how an operator may hgye inuzn. I wilidstibf erenoe to a. ;g. how the work may- Piaf; which oontriilSziis'b 9'6 seneraliy. ies-cribed in ori-- 1011* The group of i111}; asthe windin ois'zifl iiii" be unnecessary 126' forth in the introduction to this specifics I tion,'but the diagram that is furnished will readily demonstrate the feature of the invention now bein described. At each operators position t ere are indicated ten answering-jacks 6, more or less; of which are in service, 'accordin to the capacity of the operator. Single lines 9 extend to these answering-jacks, each of which is intended to indicate the group of answering-jack strands leading to said answering-jacks. Those a'nsweringjacks, as stated, that are notto be placed in operation, have their conditions artificially changed to make them correspond with answering-jacks that are already in use, so that the wire connected with these answering-jacks will not be antomatically selected. There are illustrated three divisions, I, II and III, of subscribers lines arranged in accordance with the plan outlined hitherto, there being indicated for each roup of subscribers lines two'rows IL-Z o five hundred rows of contacts, there being thirty groups of contacts in each row. The connected circles k are intended to represent all of the multiple contacts associated with a given answeringjack. For example, the connected circles A: (there being five hundred of such circles corresponding to each answeringjack) represent the tip and sleeve contact buttons 7 and 8 and any additional contact buttons, as the buttons 16, that may be associated therewith. The circles Z indicate the motor mechanism and the associated contacts 13, 5 and 6, for example, which ride over the sets of buttons Ic -k until a set is found that is associated with an idle answeringjack or an answering-jack whose circuit has not been caused to have the characteristics of a busy answering-jack. There are five hundred such devices I in association with groups I, II and III of telephone lines, one for each row, h, '5, etc., in order that the calls may be received in the order of the operators, so that no operator at one seetion need have any calls to attend to unless the'operators at the sections ahead of her have all of their cord circuits in use (considerin now the normal business of the exchange there being cord circuits m provided with answering and connectingplugs for connecting calling with called subscribers.

The first lot of five hundred contacts is (shown at the right of group No. I) is connected with the first answering-jack at 1 the first position of the first section of the "board; the second lot of such sets of conta'cts k at division No. I is connected with the first answeringjack at the second position of the first section of the board; the third lot of contacts 1.; is connected with the first ans'weringjack at the third position of the first section of the board.

The first lot of five hundred contacts (shown at the right of group No. II) is connected with the second answeringackat the firstposition of the first section of the board; the second lot of contacts is is connected with the second answeringjack at the second position of the first section of the board; the third lot is connected with the second answering-jack at the third position of 'thefirst section of the board.

The first lot of five hundred contacts is of group No. III is connected with the third ansn'cringjack at the first position of the first section of the board; the second lot is connected. with the third answering-jack at the second position of the first section of the board; the third lot is connected with the third answering a'ck at the third position of the first section of the board.

If more than nine calls are received from divisions I, Hand III at a time, the selectors I will pass by the contacts associated with the answering-jack circuits that I have mentioned at section Z of the board and will seek contacts that are not connected with a. busy answering-jack circuit, which contacts will be found in association with the answering-jacks at section No. 2, if these answering-jacks are not busy, but if the answering-jacks are busy at section No. 2, the selectors will continue in their travel to seek contacts associated with the idle answering-jacks at section N0. 3. In order that this result may be accomplished, the, fourth lot of five hundred contacts It at division No. I is connected with the first answering-jack at the first position of the second section of the board; the fifth lot of contacts is connected with the first'an swering-jack at the second position of the second section of the board; the sixth lot of contacts 70' is connected with the first answering-jack at the third position of the second section of the board,

The fourth lot of contacts I: of group No. II is connected with the second answeringjack at the first position of the second section of the board; the fifth lot of contacts is connected with the second answeringjack at the second position of the second section of the board; the sixth lot of con-v. tacts k is connected with the second answer-1 ing-jack at the third position of the second section of the board.

It will be unnecessary to further trace the different connections, as they will be apparent by an inspection of the diagram. In this way answering-jack conductors extending from the selective switching devices corresponding to each group of subscribers are subdividgdjzitoa piuga'zitgy of v groups'thai'. are cxtcnqeo answeringocks at different sections 01 the ward, .ne

restoraticn of 53.:

' said mechanism g other connections.

meat of the invezp are, as been stated, 78

' iinc-ccniacic 13 ou coli'mcs It; and 1-5- there of the invention iii? many iriore contacts '26- i-scai circui' 7 it-iii grou' of answering jack circuits being pzeicrab y assigned to the first board section, A scconrlgroup to theses-0:15; sation, the t n group to the third section; and so on. I c grouys of answering-jack circuits -11 are teiephi 1i respondi ng- .tocach group of 'zines arc cozfid-nccted witkth'c board sections iii the $221115 .4

ordr in which automatic selection .is effectedbetwcen; thccalling lines and the answering-jack circuits. That is, in the cx-- ample shown, the first group of three an- 15: swering-j ack circuits of the group of lines! is Ic'x-tendcd to the fiist boa-rd section; the "second, group to the second board;sc'cizion the third ,group to fiict'nird bou'd section. and -so on. And so with the groups of answer: ;ing-ja'ck circuitsextcndingirom' the \ihi sionIIof the lines; tho-first, group off three answerin jack circuits is extended io the first board section; the second group tothe second -section,'and so on. "Sims, each -2f5, group of telephone lines has a group of answering-"jack circuits cxtcndi'ng i'o oi- --th'c boon sc'ct-i0ns,- the the first boa-rd section being afiapi automatic connection with ca. their contactbuttons are tho i 8011111381'66. by the traveliag terzmn calling lines, the'opemtors at board section, therefore, havingno 3W ,thciv first operators have roochc ifxe 85 fpacities, the operiitors at the third tion having no work tili the opcm the second board section. are fully cc and so on. It will have also hoe-21 ob-scr that the answering-jack. circui's ciao 40 group are (iitributed omong various opera-tors positions at the so on to which said answering-jack v.circuits exten'i, -:-equalize the work of the opei'atom oac'ii :scctiomas for as possible employs l.

i -1 inrg'c or? zi-fcd in orrier wide nppica'rnI-q. of i irivezition ndiif J r. lo- 120% (icon;

oi tltwreform Wish to be shown, but

isuxontion I c to secure: by Letters- 105 includhnes provided In thesystem of inventio not be ntermediate dis-1.253;- the ncin distributing board bcing', however, prefarai: While the difi'creit s areiirrango-d in serial L that myin'vent -,dces not physical dispc ition of .to each other. aswciatcd A feature of my im'cntion r-s' answering iii-provision of i heisupplcmcntai nits; for con- 14- and 16 in addition to circuits wit? 1121s of each fclcphone changing the conjunction with the answering-jack answering-jack cuits. I idle, in soccerv 1 .60: A very useful 1 a-t-iiz', 05"13' invent och ism 5 Y 2 52nd Incohcooperation ing-plugs for engagement with said jacks, substantially as described' 2. A telephone exchange system includ ing a plurality of telephone lines provided with line-jacks and divided into groups, a plurality of answering-jack circuits for each group of telephone lines also divided into groups and extending to answering-jacks at dillerent sections of the switch-board, the answering-jacks of each group being distributed among the operators positions at each section, automatically operated selec- 'tive switching mechanism, including travel ing line-terminals and multipled answeringjack contacts engaged by said terminals, said switching mechanism being associated with the telephone lines and the answering ends of the answering-jack circuits for connecting said answering-jack circuits with calling lines, apparatus for changing the electrical character of the answering-jack circuits to cause them, when idle, to cooperate with the selective switching mechanism as if they were busy, to enable the said mechanism to pass the same into cooperation with an idle answeringjack circuit that may be used, and cord circuits in association with said answering jacks provided with answering-plugs for engagement with said jacks, substantially as described.

3. A telephone exchange system including a plurality of telephone lines provided with line-jacks and divided into groups, a plurality of answeringjacl: circuits for each group of telephone lines also divided into groups and extending to answering-jacks at different sections of the switch-board, auto matically operated selctive switching mechanism, including traveling line-terminals and multiplcd answering-jack contacts engaged by said terminals, said switching mechanism being associated with the telephone lines and the answering ends of the answering-jack circuits for connecting said answering-jack circuits with calling lines, apparatus for checking the operation of the selective switching mechanism, answeringjack circuit apparatus governing the storesaid apparatus to enable the selective switching mechanism to avoid busy answering jack circuits, apparatus for changing the electrical. character of the, ,answering-jack vcircuits to cause them, wh ch idle, to cooperate with the selective switching mechanism as it they were busy, to enable the said mechanism to pass the same into cooperation with an idle answering-jack circuit that may be used. and cord circuits in association with said answering-jacks provided with answeringplugs fore-ngagement with said jacks, substantially as described.

4-. A telephone exchange system including a plurality of telephone lines provided ith linejacks and divided into groups, a plurality of answeringjack circuits for each group of telephone lines also divided into groups and extending to answeringacks at different sections of the switch-board, the

answering-jacks of each group being dis tributed among the operators positions at each section, automatically operated selective switching mechanism, including travel-- ing line-terminals"and multipled answeringjack contacts engaged bysaid terminals, said switching mechanism being associated with the telephone lines and the answering ends of the answeringjack circuits for connecting said answering-jack circuits with .the said mechanism to pass the same into cotiperation with an idle answering-jack circuit that may be used, and cord circuits in association with said answeringjacks provided with answering-plugs for engagement with said jacks, substantially as described.

5. A multiple switch-board telephone exchange system including a plurality of telephone lines divided into groups and multipled to different sections of the multiple switch-board, a plurality of answering-jack circuits for each group of telephone linesalso divided into groups and extending to answering-jacks at difierent sections of the switch-board, automatically operated selective switching mechanism, including traveling line-terminals and multipled' answering-jack contacts engaged by said terminals,

said switching mechanism being associated with the telephone lines and the answering ends of the answering-jack circuits for con necting said answering-jack circuits with calling lines, apparatus for changing the electrical character of the answering-jack circuits to cause them, when idle, to cooperate with the selective switching mechanism as if they were busy, to enable the said mechanism to pass the same into coiiperation with an idle answering-jack circuit that may be used, and cord circuits in association with said answering-jacks provided with answering-plugs for engagement with said jacks, substantially as described.

6. A. multiple switch-board'telephone exchange system including a plurality of telephone lines divided into groups and multipled to different sections of the multiple switch-board, a plurality of answering-jack circuits for each group of telephone lines also divided into groups and extending to.

' I ciud ing' traveling line 'tez-mznals said switching 1m giid the answering en-ls of the an jack circuits with calling lines, appa:

the; said. mechanism to pass ii 'coiipemftic n with azzidle answers): phi; that niay be ilssd, and sari .associatign wifch said answez i ghange system, inoluqmg a phone hnes chvv dgd Into gzwp" pied; to dxfierent sections s1- group being dist-ribmed among the a: terminals L13- ultit'ors osxtxons at each sadism mi-am; ac-b. com-ans en bv I v 0 switching 1 aha Sm .t ne telephe:ze lmes j me, answermg- Qberatd selective switching mechanim r} I v answering 226. 5 9;

Ipled answeringfiack c ontac ciz c'uits fer connecting said answering ,assocluaiierl 31th the i eiep'uon 2 ack circuits .wx'g-h calling .Zm-es, apparaius eckmg' zim ogl' rat-isp. of the selective mechanism, ans ering-jack. cir-. cui': apparatus 5 arming the z'xt'oresa-ifi zip-.

ta the seia-qtiye switching "zisn; Sic a oid bus} answering-jack is, aopamtus for chazxging the elecmt-e1 cf the ansve-erizig-jack cit:

m, when Mia, .10 cniipemte 3 switching mechanism as :0 enable the said mechasame int?) caiipemt-iogz with 5201; circuit tha-may be r Eek Cil'ciiitS for Connecting said answering iqf changing the' electrifiil ch answering-jack circuits to cit?- iglle, t0 ciipeyata'with' the saiectms a mechanism as if they were busy,

ided with answeringwithfsai jachz-Smstmum; z-cuit-s in asseciatisnqwit-h 5 7. A multiple swit .EPZOVIClQ-Ld answergcment rim said jacks, @113 21. described. Y talegmene ska-hangs system includ-- if plumiic-y off fieiepimne lines provided.

ii1 1e-ja c s and iivi led into groups, a.

' vc rlm; jack circuits (for ines also divided 1mg to answeringmns bf the-"swim My oparated selectha mechanism including trav-eljpg switgch -bqgrd, a plurality ,nf answe; w circuits fopgach group of teiephons: 1i. glsqdivided inio groups QXtQDd answering-jacks at differs-n2;

\u. swiwh-bq'rd, antomaticaliy a e-Mimi jive switching mechanisrmi: i inglinartennmuis ink-:2 multiple-'31 answering jilcklcqntgctsengaged by. said tannin-m C? said switchjhgmechanism being; assuciatea' lf'l?1@"t irmim11S ml militiglec answqringr fi th the telephone lines and the answei-ing 3:1;5. coptaqts engagQd -by" sglci term-mats,

grids dftlie :insptting-jac'- circuits; fur consa 1d swatchmg mechpmsxn bemg assoclgted necti-ng said izhsx sring-jzz g l' circu with Wit-h tip; telephone hpe s andfihe answering pgl lixig lines 'hPp tus for ch ciii g th ends 02'; the znswgrmgqack clrcmbsfor con- 3,I 1 s Wering-jacli .changmg. the elect-meal cm i ntd coiiperation with an group being ;.d i st-ributed among tbs jacks, .px ovidedwith. answering-plug i01- answering-jacks at differentsect-ions nesting szi answering-jack cii'cuitsi with peration of the selctive- 3wit0111ng-n1acha v the first group of answering id nism, answering-jack circuit apparatus govv rning theaforesaid apparatus to 9223.17 the J col esponding to eac}: group sqlectlve swltchmg mecnamszn to 5:. 1 of :mes extra-13mg. to me filst rm ecci0n, the secend group to ch imard sectlon, and so 011',

mechanism operating with;

- circuits, ap'm selective answering-jackcircuitsto 19 iie answering- 1 use, we cam said. agswez-mg answeringfiack 'circyits are ccn'nected with fine 5m -bf zu(l sections, and, corfi cicpuits wit Sfliil answering-iacks a'n swsging-phzgs for engage-- yaks s'qbsbg tmlly asfde jack circuit (that may be circmtsm assocmtzon mm engagement with des'cribei. L

'8. ;A nhiltip1e.swit=;h-b0ar& taiep'izqn change sysfiam' includ ing 5 plur-sE-i v phon lihesdivided min and J: filed to difierent secfiions 01" mu ysem includ iity 0'5 telephone viti1-iinp-,=.ui1-:s' 'and divided into groups,..& "p11: raIi t 3- of answering-jack g1" rcl l:1t f0r gash ,ga'c'up of telephonelines also Qzneli mto grui'ips and. extending to answenngacks at 'also div ided .60 groups and extending in I m '1 answeymgqucks or eaetx. group bemg 11g- I t-z-i'mxtsd among the operai-ars 90351011533 czzch' section,- amtomaticaiiy operated sglecswitch-50am; the: answering-gals of tors positions-at aQc' -sciion,-auim 1 ti've switdtiipg mechanism including trm"e1. operated: slective' Switching mechanism, 511- ing Line-terminals and muitlpled-cord cm- 130.

Lines provided,

diifervnt sections of 5m switch-'boarijhe 1'26" tacts engaged by said terminals, said switching mechanism being associated with the telephone lines and the answering ends of the answering-jack circuits for connecting said answering-jack circuits with calling lines, the first group of answering-jack circuits correspondin to each group of telephone lines extending to the first switchboard section, the second group 'to the sec- Y 0nd switch-board section, and soon, said selective mechanism operating with the answering-jack circuits to connect the idle answerlng-jack circuits with calling lines in the order in which the groups of answeringjack circuits are connected with the switchboardsections, and cord circuits in association with said answering'jacks provided with answering-plugs for engagement with said jacks, substantially as described.

11. A telephone exchange system includ ing a plurality of telephone lines provided with line-jacks and divided into groups, a plurality of answering-jack circuits for each group of telephone lines also divided into groups and extending to answering-jacks at diflerent sections of the switch board, automatically operated selective switching mechanism including traveling line-terminals and inultipled answering-jack contacts engaged by said terminals, said switching mechanism being associated with the telephone lincs and the answering ends of the answering-jack circuits for connecting said answeringjack circuits with calling lines, apparatus for checking the operation of the selective switching mechanism, answeringjack circuit apparatus governing the aforesaid apparatus to enable the selective switching mechanism to avoid busy answering-jack circuits, the first group of answering-jack circuits corresponding to each roup of telephone lines extending to the irst switch hoard section, the second group to the second'switch-board section, and so on, said selective mechanism operating with the answering-jack circuits to connect the idle answeringjack circuits with calling lines in the order in which the groups of answering-jack circuits are connected with the switch-board sections, and cord circuits in association with said answeringjacks provided with answeringplugs for engagement with said jacks, substantially as de scribed.

12. A telephone exchangesystem including a plurality of telephone lines provided with line-jacks and divided into groups, a plurality of answering-jack circuits for each group of telephone lines also divided into groups and extending to answeringjacks at different sections of the switch-board, the ans'weringjacks of each group being distributed among the operators positions at section, automatically operated selec tive switching mechanism including traveling line-terminals and multipled answeringack contacts engaged by said terminals, said switching mechanism being associated with the telephone lines and the answering ends of the answering-jack cir- 1-3 cuits for connecting saidanswering-jack cirgroups of answering-jack circuits are connected with the switch-board sections, and cord circuits in association with said answering-jacks provided with answerin plugs for engagement with said jacks, su 9O stantially as describedv 13. A telephone exchange system including a plurality of telephone lines provided with line-jacks and divided into groups, a plurality of answering-jack circuits for each group of telephone lines also divided into groups and extending to answeringjacks at different sections of the switchboard, automatically operated selective switching mechanism. including traveling line-terminals and multipled answering-jack contacts engaged by said terminals, said switching mechanism being associated with the telephone lines and the answering ends of the answering-jack circuits for connect- 10; ing said answering-jack circuits with calling lines, apparatus for changing the electrical character of the answering-jack circuits to cause them, when idle, to cooperate with the selective switching mechanism as if they were busy, to enable the said mechanism to pass the same into cooperation with an idle answering-jack circuit that may be used, the first group of answering-jack circuits corre* sponding to each group of telephone lines 1 1 extending to the first switch'board section, the second group to" the second switch-board section, and soon, said selective mechanismoperating with the answering-jack circuits to connect the idle answering-jack circuits with calling lines in the-order in which the j groups of answering-jack circuits; are connected with the switch-board sections, and cord circuits in'association with said aiiswering-jacks provided with answering-plugs for Z engagement with said jacks, substantially as described. v I l. A telephone exchange-systeminclud L ing a plurality of telephone lihes provide with line-jacks and divided into'ggroups, a

' answer extending iisliy as some into bobsingfiark oizmfi Y group or ailswaimg ucs on spending the s'ccon section opcmt r to com war: 3 with caning Zims in me order in which the groups of answ ring-jacl: circuits are. conhec tef r, switchboard sea-Zions, and cord circuits in association with said answarmg-jacks :a-ie-:1 will z-ansn-ez-ing-phgs for enga e-ment wish sai'ci jocks, suiosian- 1'. lephonsexchange systemg a, p out of telephone imes with 1 re-jacc and diviried into plurality "of szaswering-jaclc c each into gro J. 'acks at @1581'2111} fisleyhone iinss an ext-ending =':o

sections oj't' oars, automatically operate-:1 switcnu'zg mechamsm mind-12g lineierminess and took contacts engaged switching mechanism 5 theltelephone Zines Q $5 $116 ansrisring-jack circuits for sooner? g jaok circnii-s with Calling ngsaidi answen" fines, apparatus for che-akmg the ogr-ez gt-ion or the ctive switching mach swering-jack circuitappnra the aforesaid n t-parsing to am the swiiching mechanism ovoid bus? f governjn 'ihe sewean's .s'ering circui-': spool-ems 'ehanging the electrical ch12 me:- of the 2.51 ck circuits to cause 112211. when idl, to com. crate-wish tho selective swjtb ing mecmm 'r' they were 3 his the into (oops-rain); circuii nag-3am.

mism,

. suits group to the sco'nd switch-board section, and so on,-

nri soled-ire mechanism operatwith the agmierirlg-jack circuits'to son'- mo? the. idle aiwxering-jack circuits with min-Hing in the order in which the cups 0: v:mssarong-3ask cnicults'are con.-

' the s3? nrevicied went i ad

with answeringeirpsc-ue lines provided :uuuz mix-mg :112 op-crtors positions at h seq-i011 automatically operated Selecg mechanism -iz 1c1uding tram e-tsrzoinais and m" tioled answerf' s-'itc':1 ing mechanism being associated with the 'teieghonerlines and the answering ends of the answering-jack circuits for conneoting said :msWsring-jackcirbuits with *eafiling line-s, apparatus for checking the ojperation of nism, ansvreriag-jackcircuit apparatus gov earning the aforesaid appgratils'ro enable the selective swiuching mechasoiacti'va switching mechanism to avoid busy r'lswermg- 51:1: cu'cmt's, apparatus for g mg th s ecctncal'characterof the ansoaring- W5: circuits corresponding to cash group of teleyhone lines extending to ation with said any w'th said jacks, suo- I each grou being disexchange, system incintl- .rp'icied into groups, :2

$1.- imsvvering-mcks at entacts engaged by said terminals,

1" circuits to cause them, when cooperate-With the selective switchif they; vera busy, to en! v said mscimnisn to pass the same v 21%, may be used, the first group the fiastswit h-bozu'ci section, the second group to the second switch-board soot-ion,

coiling line-s in the order in which the. groups of answerh! jack circuits are connected -ch-nmu'd sectxons. and cord err- ;t-h said jacks substantially as .vitch-board telephoxigv exnclnding a plurality oi talehangs s i in diifsrcntsactions of the q iultiple \"i =rts for ea. .2: group of talsphslil'lilkes fiscdlvzcisql into groups and "ax'tendmg'gto ines (1i "bird into groups andfmul-q is: association with said answering I jar-i prm'iderl with answering-plugs for 120.

oaz'd, a plum'iity of answerm'gjarkswitch board, automatically operated selec tive switching mechanism including traveling line-terminals and multipled answering- ]ack contacts engaged by said terminals,

said switching mechanism being associated ond switch-board section, and so on, said selective mechanism operating with the answering-jack circuits to connect the idle answering-jack' circuits with calling'lines in the order in which the groups of answeringjack circuits are connected with the switchboard sections, and cord circuits .in association with saidanswering-jacks provided with answering-plugs for engagement with said jacks, substantially as described.

18. A multiple switchboard telephone exchange system including a plurality of telephone lines divided into groups and multipled to difiierent sections of the multiple switchboard, a plurality of answering-jack circuits for each group of telephone lines also divided into groups and extending to answering-jacks at different sections of the switch-board, the answeringjacks of each group being distributed among the operators positions at each section, automatically operated selective switching mechanism including traveling line-terminals and multipled answering-jack contacts engaged by said terminals, said switching mechanism being associated with the telephone lines and the answering ends of the answeringjack circuits for connecting said answeringjack circuits with calling lines, the first group of answering-jack circuits corresponding to each group of telephone lines extending to the first switchboard section,

.the second group to the second switch-board section, and so on, said selective mechanism operating with the answering-jack circuits .to connect the idle answeringjack circuits with calling lines in the order. in which the groups of answeringack circuits are connected with the switch-board sections, and .cord circuits in association with said answering-jacks provided with answeringplugs for engagement with said jacks, substantially as described.

'19. A multiple switch-board telephone exchange system including a plurality of telephone lines divided into groups and'multipled to different sections of the multiple switch-board, a plurality of answering-jack circuits for each group of telephone lines also divided into groups and extending to answering-jacks at different sections of the switchboard, automatically operated selective switching mechanism including traveling line-terminals and multipled answering-jack contacts engaged by said terminals, said switching mechanism being associated with the telephone lines and the answering ends of the answering-jack circuits for connecting said answering-jack circuits with calling lines, apparatus for checking the operation of the selective switching mechanism,'answering-jack circuit apparatus governing the aforesaid apparatus to enable the selective switching mechanism to avoid busy answering-jack circuits, the first group of answering-jack circuits corresponding to each group of telephone lines extending to the first switch-board section, the second group to the second switchboard section, and so on, said selective mechanism operating with the answering-jack circuits to connect the idle answering-jack circuits with calling lines in the order in which the groups phone lines divided into groups and multi-' pled to different sectionsof the multiple switch-board, a plurality o answeringjaclr' circuits for each group of telephone lines also divided into groups and extending to answering-jacks at different sections of the switch-board, the answering-jacks of each group being distributed among theoperators positions at each section, automatically operated selective switching mechanism including traveling line-terminals and multipled answering-jack contacts engaged by said terniinals, said switching mechanism being associated with the telephone lines and the answering ends of the answeringjack circuits for connecting said answeringjack circuits with calling lines, apparatus for checking the operation of the selective switching mechanism, answeringjack circuit apparatus governing the aforesaid apparatus to enable the selective switching mechanism to avoid busy answering-jack circuits,.the first group of answering-jack circuits corresponding to each group of telephone lines extending to the first switchboard section, the second group to the second change system including a plurahf phone lines divided into group" pied to different sccl'zicns of switch-board, a plurality of mi circuits fer each groin) 0i iele also divided into groups an fills\ifil'lflg-jQICkS at difi'ercnt .ii 7 switch-beard, automatically epcuiwl tivc switching mechan in including ing linetcrininzils and inull'i i in fack c icl Sn'iiz i; 1;; incchan with (he telephone line. ends 0? the answering-jack ucct-ing :l circuits; nith cull pal-nine fer c mngring ch 4 f t. ing-jack circu n 21 iulc. to cuiiperate u clutching mechanism as if '50 enable the said incchaisi S3112!) into cc incl circui being the ing' to the hie,

cud grain) to the sew-nil ticru and so cr said nclccth l 'iecl crating with the nu fi cu mnuect the irlle {wan (*l'll'lQjiKn-Z circa calling l nes 1'; thc mwlcr in which the of :1havering-jack circuits are con: with the switch-hoard Fccii-fm.- and cor circuits in nsflccintiou Vii uhl nnsn'eri provided with m for chang- 9? 0? the n n swcrir ucnfi; with said jn i, when ii lc, t0 cc 100 il ecli swilching llllEClli- 22 A multiple switchbcarcl iclcphcne c Pllfiljlfl the said 7 change system including a plurality of Ielc 1 ssic 0. phone lines divided into groups nml igjacli c; H ihiu; 1)l{ \l to different seciicns cf the in ii zinewcrir 105 swiich-hmirl'l, a plurality of u- Circuits for each group 0i? ti also divided into groups and nnsivering jncks at (liflercnt sect V aim so (in, Hiiiil switclehczu'd, the answcringqnclis of each iciziling with the an 136 g'rnup being distributed amonq the open 1 Jrnnwr. the idle 5111-- tors positions at each section mitmnalticn y lines in operated selective switching mechanism 1% answering chuling traveling line-terminals and multiwill the S\ iCCl1- pied nnsrvcringjhck contacts engaged by circui- 's in assccin- 1 said terminals, said svvitching incchzi "iQ'lK prm'idccl being a *sceiulc-(l with the telephone line 9 it with the answering ends of the answcrin J u 1 \l m circuits, for connecting said answering aclc )czirrl telephone ex" circuits with calling lines, apparatus for :1 plurality of 1 0 changing the electrical character Uf the 211igreups and multisueringjuck circuits to cause thenn hen cf the multiple idle, to co'cipcratc with the selcctirc snitch of any-"raring ing mechanism as if they were busy, in encl tclcphonc lincs ahle the said mechanism to pass the same cums will eiilcncling in 5 into cciiperzition with anirlle an 1 incl; circuit that may he used, the first gi' up of answering-jack circuits correspomliz nch group of telephone lines extending the first snitch-board section. the seccnc ti :urm'ci acks of cnch fluzieil liming the pcra V u'li sccfion, automatically itching mechanism in- 1 ul sections 0:" 

